Science: Scientists in Baton Rouge, Louisiana, gave runners two cups of either chicken-noodle soup or water before a 90-minute run in the heat. Compared to those who had water prerun, runners who ate the soup had better hydration and electrolyte levels postworkout. Researchers think the soup's sodium made subjects thirstier, which encouraged them to drink more.Action: Before a hot run, have some soup with about 800 milligrams of sodium per cup to promote drinking midrun.

Tea can reduce muscle soreness

Science: Exercise physiologists from Rutgers University gave participants a black-tea extract or placebo for nine days and put them through a strenuous workout. Compared to the placebo group, participants who received black-tea supplements had significantly lower amounts of muscle soreness and damage. Researchers believe catechins, the antioxidants in black and green tea, were responsible for reducing inflammation.Action: Drink one or two cups of black or green tea a day to increase the amount of catechins in your diet and perhaps stave off muscle soreness.

An apple a day keeps the doctor away

Science: Researchers at the University of South Carolina gave lab animals a supplement of quercetin, a compound found in apples, for several days. They ran the animals on a treadmill until exhaustion and inoculated them with the influenza virus. Animals that received the quercetin supplement were less likely to get sick than those that did not receive the supplement.Action: Make foods high in quercetin (apples, onions, garlic, and broccoli) part of your diet, especially after an intense or long run, when your immune system is fragile.

Caffeine can help you set PRs...

Science: Scientists at two universities in Minnesota gave runners a drink with or without caffeine (equal to two cups of coffee) one hour before a VO2 max test. Participants who had caffeine experienced a four percent increase in VO2 max and a three percent increase in lactate threshold. This performance boost can translate into a 30-second improvement in 10-K time.Action: Have one or two cups of coffee or tea an hour before a hard workout or race for a potential drop in times.

...And helps speed recovery, too

Science: Researchers in Melbourne, Australia, put participants through two bouts of exhaustive exercise to drain glycogen stores. Researchers then gave the athletes a large dose of carbs either with or without caffeine. Within four hours, caffeine boosted glycogen rebuilding by 66 percent compared to carbohydrate alone.Action: After a hard run, refuel with a carb-rich meal along with coffee, tea, or a caffeinated energy drink to boost recovery.